Heat energy supply system and method, and reconstruction method of the system

ABSTRACT

A heat energy supply system and method capable of drastically increasing energy efficiency and energy supply efficiency, as well as a reconstruction method of the heat energy supply system. The heat energy supply system comprises a boiler for heating a heat medium and producing steam including water and other vapors, a heat pump including a steam turbine driven by the steam supplied from the boiler and a heat exchanger for heating the heat medium by employing waste heat or heat obtained from environment, thereby producing the steam at a setting temperature, and a steam supply line for supplying the steam discharged from the steam turbine and the steam heated by the heat exchanger to a heat utilization facility.

CROSS-REFERENCE

This is a continuation application of U.S. Ser. No. 11/304,626, filedDec. 16, 2005 now U.S. Pat. No. 7,669,418.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat energy supply system and methodfor supplying heat energy to a heat utilization facility, and alsorelates to a method of reconstructing the heat energy supply system byutilizing the existing equipment.

2. Description of the Related Art

As one proposal aiming to improve energy efficiency of a heat energysupply system, there is known a combination of a cogeneration system anda heat pump (see, e.g., Patent Document 1: JP, B 7-4212). The heat pumpis to take in atmospheric heat, waste heat, etc. In that related art,hot water and cold water produced by the heat pump are utilized aswashing water, cooling water, etc. in a facility.

Also, in a system using a heat pump alone without generation of electricpower, it is proposed to utilize, as a medium, water instead of Freonthat has hitherto been used (see Patent Document 2: JP, A 2001-147055).

SUMMARY OF THE INVENTION

In the case of supplying heat energy to a heat utilization facility,however, it is difficult to maintain an amount of energy transferableper unit medium weight at a sufficient level even with hot water andcooling water used as heat mediums. For that reason, even when the hotwater and the cooling water produced by using the heat pump are suppliedto the heat utilization facility according to the above-mentionedrelated art, the installation place of a heat energy supply system islimited to an area near the heat utilization facility.

Further, it is known that, by utilizing water as a heat medium in theheat pump, steam (water vapor) having high energy density can be used asa heat medium. However, large motive power is required to compress thesteam having low density, and practical use of such a system is limited.

In view of the state of the art described above, an object of thepresent invention is to provide a heat energy supply system and methodcapable of drastically increasing energy efficiency and energy supplyefficiency, as well as a reconstruction method of the heat energy supplysystem.

To achieve the above object, the heat energy supply system of thepresent invention comprises a boiler for heating a heat medium andproducing steam including water and other vapors, a heat pump includinga steam turbine driven by the steam supplied from the boiler and a heatexchanger for heating the heat medium by employing external, therebyproducing the steam at a setting temperature, and a steam supply linefor supplying the steam discharged from the steam turbine and the steamheated by the heat exchanger to a heat utilization facility.

According to the present invention, energy efficiency and energy supplyefficiency can be drastically increased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a first embodiment of the presentinvention;

FIG. 2 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a second embodiment of the presentinvention;

FIG. 3 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a third embodiment of the presentinvention;

FIG. 4 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a fourth embodiment of the presentinvention;

FIG. 5 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a fifth embodiment of the presentinvention; and

FIG. 6 is a system flowchart showing the overall arrangement of a heatenergy supply system utilizing water as a heat medium, the systemincluding a known heat pump.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Cogeneration systems according to embodiments of the present inventionwill be described below with reference to the drawings.

(1) First Embodiment

FIG. 1 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a first embodiment of the presentinvention.

As shown in FIG. 1, the heat energy supply system of this embodimentcomprises a gas turbine 10 serving as an engine for convertingcombustion energy to a driving force, a boiler (waste heat recoveryboiler) 30 operated using, as a heating source, exhaust gas from the gasturbine 10, a heat pump 50 driven by steam from the boiler 30, and asteam supply line 70 for supplying steam produced by the heat pump 50 toa heat utilization facility 1.

(1-1, 1) Arrangement of Gas Turbine 10

The gas turbine 10 comprises a compressor 11 for sucking and compressingthe atmosphere (air) A, a combustor 12 for burning fuel B together withthe compressed air from the compressor 11 and producinghigh-temperature, high-pressure exhaust gas, and a turbine 13 forobtaining rotatory power through expansion work of the exhaust gas fromthe combustor 12. The fuel used in the combustor 12 may be, for example,natural gas, town gas containing natural gas as a main component, lampoil, light oil, or diesel fuel. In this embodiment, a generator 14 iscoaxially coupled to the compressor 11. The rotatory power obtained fromthe turbine 13 is transmitted to the generator 14 for conversion toelectrical energy. Note that, instead of the generator, other suitableload equipment, such as a pump, may be coupled to the gas turbine 10.

(1-1, 2) Arrangement of Boiler 30

The boiler 30 heats a heat medium to produce steam by using the exhaustgas from the gas turbine 10. An outlet for the exhaust gas passingthrough the boiler 30 is connected to a stack 43. When it is required toreduce the nitrogen concentration in exhaust gas C released to theatmosphere through the stack 43, denitration equipment (not shown)filled with a catalyst is preferably installed in the boiler 30 so thatmost of nitrogen oxides contained in the exhaust gas C is decomposed tooxygen and nitrogen which are harmless.

The boiler 30 comprises four heat exchangers, i.e., a low pressureeconomizer 31, a high pressure economizer 32, a high pressure evaporator33, and a high pressure super-heater 34, which are installed in thisorder from the downstream side in the direction of flow of the exhaustgas. In the boiler 30, heat energy contained in the exhaust gas isrecovered by those four heat exchangers 31-34, thereby heating a heatmedium supplied by a circulation pump 35. The circulation pump 35 hasthe function of supplying, to the boiler 30 in a circulating manner, theheat medium that has been supplied from the heat pump 50 to the heatutilization facility 1 and then condensed after being utilized as a heatsource in the heat utilization facility 1. When the heat medium requiresto be cleaned depending on the conditions in use of steam inside theheat utilization facility 1 or corrosion of piping, desalinationequipment (not shown) filled with an ion exchange resin, for example, ispreferably installed upstream of the circulation pump 35.

The heat medium introduced to the boiler 30 by the circulation pump 35passes through the low pressure economizer 31, the high pressureeconomizer 32, the high pressure evaporator 33, and the high pressuresuper-heater 34 in this order. Pipes 37, 38 branched at a branch point36 are connected to the low pressure economizer 31 at its downstreamside in the direction of flow of the heat medium. The pipe 37 isconnected to the high pressure economizer 32 through a high pressurepump 39, and the pipe 38 is connected to the heat pump 50 through acontrol valve 40. The high pressure economizer 32 and the high pressureevaporator 33 are connected to each other through a steam drum 41. Thesteam drum 41 is connected to the high pressure super-heater 34positioned at the most downstream side in the direction of flow of theheat medium. Further, the high pressure super-heater 34 and the heatpump 50 are connected to each other through a pipe 42.

When the temperature of the exhaust gas lowers through the heat exchangewith the heat medium in the heat exchangers 34, 33, 32 and 31, therearises a possibility that water vapor contained in the exhaust gas iscondensed on a heat surface of the low pressure economizer 31, etc. andcauses piping corrosion. Therefore, piping materials of the low pressureeconomizer 31, etc. are preferably made of stainless steel or plastichaving superior corrosion resistance. Depending on cases, the lowpressure economizer 31, etc. may be divided into an upstream part and adownstream part in the direction of flow of the exhaust gas, and onlythe downstream part subjected to lower temperatures may be made ofstainless steel. Further, an exhaust gas outlet portion of the boiler 30and an inner wall surface of the stack 43 may be lined with stainlesssteel or plastic.

(1-1, 3) Arrangement of Heat Pump 50

The heat pump 50 comprises a steam turbine 51 driven by the heat medium(steam) supplied from the boiler 30 through the pipe 42, a two-phaseflow expansion turbine 52 and a compressor 53 which are coaxiallycoupled to the steam turbine 51, and a heat exchanger (evaporator) 54for heating the heat medium (for example, high temperature water), whichhas been preheated by the low pressure evaporator 31 in the boiler 30and branched into the pipe 38 through the branch point 36, by utilizingexternal heat (such as waste heat from the heat utilization facility 1or heat obtained from environment). The high pressure super-heater 34 isconnected to the steam turbine 51 through the pipe 42, and the lowpressure economizer 31 is connected to the heat exchanger 54 through thepipe 38.

A pipe 55 through which a heating medium for heating the heat mediumsupplied to the heat utilization facility 1 flows is disposed inside theheat exchanger 54. The pipe 55 is connected to the two-phase flowexpansion turbine 52 at its downstream side in the direction of flow ofthe heating medium and to the compressor 53 at its upstream side. Also,the two-phase flow expansion turbine 52 is connected to an evaporator 57through a pipe 56, and the evaporator 57 is connected to the compressor53 through a pipe 58 so that the heating medium is circulated in aclosed system. In this embodiment, trifluoroethanol (TFE), for example,is preferably used as the heating medium. As an alternative, theatmosphere or water (e.g., river water) may also be used if thetemperature of the atmosphere or water can be increased to a levelsufficient to heat the heat medium supplied to the heat utilizationfacility 1 to a setting temperature with pressure adjustment in thetwo-phase flow expansion turbine 52 and the compressor 53.

The evaporator 57 has the function of taking in external heat forapplication to the heating medium introduced to the heat exchanger 54.Thus, the heat exchanger 54 heats the heat medium (for example, hightemperature water) from the boiler 30 through heat exchange of theexternal heat with the recovered heating medium. When the heat sourcehas a low heat transfer rate such as the case of using, e.g., theatmosphere as the heat source, a fan 59 may be installed, as shown, toincrease the heat exchanger efficiency between the environment and theheating medium.

(1-1, 4) Arrangement of Steam Supply Line 70

The steam supply line 70 is a piping line for supplying the steam fromthe heat pump 50 to the heat utilization facility 1 as required. In thisembodiment, the steam supply line 70 comprises a pipe 71 connected atits upstream end to an outlet (or an extraction port) of the steamturbine 51, a pipe 72 connected at its upstream end to the pipe 38through the heat exchanger 54, a joining unit 73 connected to respectivedownstream ends of the pipes 71, 72, and a pipe 74 connecting thejoining unit 73 and the heat utilization facility 1. In this embodiment,the steam discharged from the steam turbine 51 and the steam heated bythe heat exchanger 54 are joined and mixed together in the joining unit73 after passing through the pipes 71, 72, respectively, and are thensupplied to the heat utilization facility 1.

(1-1, 5) Construction of Heat Energy Supply System

When constructing the heat energy supply system of this embodiment, theentire system can be of course newly constructed, but if there isexisting equipment such as an engine and a boiler, it is also possibleto reconstruct the system by employing the existing equipment.

For example, if the gas turbine 10 already exists, the heat energysupply system is constructed as follows. The boiler 30 is connected tothe gas turbine 10 so as to heat the heat medium by the exhaust gas fromthe gas turbine 10, thereby generating steam. The heat pump 50 isadditionally installed and connected to the boiler 30 such that thesteam turbine 51 is driven by the steam from the boiler 30 and the heatmedium preheated by the boiler 30 is heated by the heat exchanger 54 togenerate steam. Then, the heat pump 50 and the heat utilization facility1 are connected to each other through the steam supply line 70 such thatthe steam discharged from the steam turbine 51 and the steam heated bythe heat exchanger 54 are supplied to the heat utilization facility 1.The heat medium condensed after being utilized as a heat source in theheat utilization facility 1 is circulated to the boiler 30 by thecirculation pump 35.

As another example, if the boiler 30 (or any other boiler) alreadyexists, the heat energy supply system can be constructed by modifyingthe existing boiler to be supplied with the heat medium from the gasturbine 10, and then by installing the heat pump 50, the steam supplyline 70, and the circulation pump 35 in a similar manner to thatdescribed above. While the heat medium branched from the heat medium fordriving the steam turbine 51 is used as the heat medium supplied to theheat exchanger 54 of the heat pump 50 in this embodiment, different heatmediums from separate supply sources may be used for the steam turbine51 and the heat exchanger 54 if there is another heat-medium supplysource.

The operation of the heat energy supply system according to the presentinvention will be described below.

(1-2, 1) Operation of Gas Turbine 10

When the atmosphere (air) A having been deprived of foreign mattersthrough a filter (not shown) is sucked into the compressor 11, the airis compressed by the compressor 11 and pressurized to a setting pressure(e.g., about 8 atm). Simultaneously, the air sucked into the compressor11 is heated under pressurization to a setting temperature (e.g., about250° C.). The compressed air from the compressor 11 is burnt in thecombustor 12 together with the fuel B, to thereby produce thehigh-temperature, high-pressure exhaust gas. When the exhaust gas issupplied to the turbine 13, the turbine 13 is given with rotatory powerthrough expansion work of the exhaust gas, and the rotary power istransmitted to the generator 14 for conversion to electrical energy.

(1-2, 2) Operation of Boiler 30

The boiler 30 is supplied with, as a heat source, the exhaust gasdischarged from the turbine 13 after making the expansion work therein.The exhaust gas supplied to the boiler 30 has a high temperature (e.g.,about 560° C.) near an outlet of the turbine 13, but the exhaust gastemperature gradually lowers through the successive heat exchanges withthe heat medium supplied by the circulation pump 35 while passingthrough the heat exchangers 34, 33, 32 and 31 until the exhaust gas isdischarged from the stack 43.

The heat medium at a predetermined temperature (e.g., about 30° C.),which has been condensed after being used as a heat source in the heatutilization facility 1, is first pressurized by the circulation pump 35to a setting pressure (e.g., about 0.6 MPa). Then, the heat medium issupplied to the low pressure economizer 31 and is heated to a settingtemperature (e.g., about 100° C.). Simultaneously, the pressure of theheat medium in the state of high temperature water is reduced to apredetermined pressure (e.g., about 0.5 MPa) due to pressure loss in thelow pressure economizer 31. The heat medium is then distributed to thepipes 37, 38 through the branch point 36. A flow rate ratio at which theheat medium is distributed to the pipes 37, 38 at that time is adjusteddepending on the opening degree of the control valve 40.

The heat medium introduced to the pipe 37 is pressurized to a settingpressure (e.g., about 5.4 MPa) by the high pressure pump 39, and is thenheated to near a saturation temperature (269° C.) by the high pressureeconomizer 32. When the heat medium in the state of saturated water issupplied to the steam drum 41, it is heated by heat energy of theexhaust gas in the high pressure evaporator 33 in a naturallycirculating manner for phase change into steam. Inside the steam drum41, the saturated water and the saturated steam are separated from eachother depending on density difference between them, and the saturatedsteam is transferred from an upper gas-phase region to the high pressuresuper-heater 34. The heat medium is heated and pressurized in the highpressure super-heater 34 to become super heat steam having a settingtemperature and pressure (e.g., about 450° C. and about 5.0 MPa), andthe heat medium in the form of super heat steam is supplied to the steamturbine 51 serving as a motive power source of the heat pump 50.

(1-2, 3) Operation of Heat Pump 50

The heat medium (super heat steam) exiting the high pressuresuper-heater 34 at a setting pressure (e.g., about 5.0 MPa) performsexpansion work in the steam turbine 51 and is discharged from the steamturbine 51 after being depressurized to a setting pressure (e.g., about0.4 MPa) suitable for use as a heat source in the heat utilizationfacility 1. The rotatory power obtained by the steam turbine 51 istransmitted to the two-phase flow expansion turbine 52 and thecompressor 53 for driving them.

The heating medium (e.g., TFE) flowing through the pipe 58 at apredetermined pressure (e.g., about 0.03 MPa) is compressed andpressurized to a setting pressure (e.g., about 1.1 MPa) by thecompressor 53. The heating medium heated with the compression issupplied to the heat exchanger 54 for heat exchange with the heat mediumthat is supplied from the boiler 30 through the pipe 38 and has thepredetermined temperature (e.g., about 100° C.). The heat medium isthereby evaporated to become saturated steam having a settingtemperature and pressure (e.g., about 140° C. and about 0.4 MPa).

The heating medium having been subjected to the heat exchange in theheat exchanger 54 is condensed into a liquid, and when the liquidundergoes adiabatic expansion and is depressurized to a setting pressure(e.g., about 0.03 MPa) in the two-phase flow expansion turbine 52, apart of the liquid is evaporated and a two-phase flow is obtained at alowered setting temperature (e.g., about 45° C.). Thus, because of suchadiabatic expansion causing depressurization to the low pressure and thetemperature drop, the heating medium in the heat pump 50 is able toabsorb the external heat with very high efficiency. The heating mediumin the state of the two-phase flow is heated by the evaporator 57 by,e.g., waste heat obtained from the heat utilization facility 1 at apredetermined temperature (e.g., about 50° C.) for phase change intovapor. If there is no suitable factory waste heat from the heatutilization facility 1, the pressure of the heat medium may be furtherreduced to be evaporated by heat of the atmosphere as described above.In that case, since the heat transfer efficiency of gas, such as theatmosphere, is relatively low, the heat exchange efficiency in theevaporator 57 can be increased by providing the fan 59, as shown, sothat heat transfer is promoted.

(1-2, 4) Operation of Steam Supply Line 70

The steam discharged from the steam turbine 51 and the steam obtainedfrom the heat exchanger 54 are joined and mixed together in the joiningunit 73 after passing through the pipes 71, 72, respectively, and arethen supplied to the heat utilization facility 1 through the pipe 74 foruse as a heat source therein. After being condensed upon release of theheat in the heat utilization facility 1, the heat medium is dischargedfrom the heat utilization facility 1 and is returned to the circulationpump 35 through a proper cleaning process, as required. Then, the heatmedium is supplied again to the boiler 30 by the circulation pump 35 ina circulating manner.

(1-3) Operating Advantages

With this embodiment, since the heat medium in a vapor (steam) state issupplied to the heat utilization facility 1, an energy amounttransferable per unit medium weight can be drastically increased incomparison with the case of supplying the heat medium in a liquid state.Accordingly, power required for transporting heat can be reduced, thusresulting in that the installation place of the heat energy supplysystem is not limited to an area near the corresponding heat utilizationfacility 1 and a wide variety of applications can be realized. Further,since the heat pump 50 is employed to produce the steam supplied to theheat utilization facility 1, it is possible to take, into the system,not only the heat energy of the boiler 30, i.e., the fuel energy appliedto the gas turbine 10, but also the waste heat of the heat utilizationfacility 1, which is released without being utilized, or heat energyinfinitely present in environment, and to drastically increase theenergy efficiency.

For example, if high temperature water of 100° C. is produced takinginto account a temperature drop occurred during transport of the heatmedium from the heat pump 50 to the heat utilization facility 1 oncondition that the heat medium temperature required by the heatutilization facility 1 is 50° C., the amount of heat energy per unitweight of the heat medium transported is 0.21 MJ/kg by calculation. Onthe other hand, when steam of 100° C. is produced, the amount of heatenergy per unit medium weight is 2.7 MJ/kg by calculation because oflarge latent energy. Stated another way, by supplying the heat medium ina steam state to the heat utilization facility 1, the amount oftransported heat energy per unit medium weight is increased 13 timesthat resulting when the high temperature water is used.

Let here suppose, for example, the case where the heat medium iscompletely evaporated in the high pressure super-heater 34 to producesteam at a setting temperature and pressure (e.g., about 450° C. andabout 5.0 MPa) in the boiler 30. In this case, assuming that thetemperature of the heat medium supplied to the low pressure economizer31 is 30° C., the enthalpy of that heat medium is 125 kJ/kg. On theother hand, because the enthalpy of super heat steam at 450° C. is 3315kJ/kg, calorie of 3190 kJ/kg has to be added to the heat medium in theboiler 30 in order to raise the temperature of the heat medium to 450°C. Assuming the heat medium to be saturated water at 269° C. at the timewhen the heat medium flows into the high pressure evaporator 33, calorierequired for heating the heat medium from such a state to become thesuper heat steam at 450° C. through phase change is 2137 kJ/kg that is67% of total exchanged calorie (3190 kJ/kg) required in the entireboiler 30.

On that occasion, to enable heat to be transferred from the exhaust gasto the heat medium (saturated water) in the high pressure evaporator 33,the temperature of the exhaust gas near the high pressure evaporator 33must be 10° C. or more higher than the saturation temperature (269° C.),and therefore that exhaust gas is required to have at least atemperature of 279° C. In this case, assuming that the temperature ofthe exhaust gas immediately after being discharged from the turbine 13is 560° C., it lowers by 281° C. until reaching 279° C. near the highpressure evaporator 33.

On the other hand, calorie required for heating the heat medium suppliedto the boiler 30 at 30° C. to 269° C. until the heat medium flows intothe high pressure evaporator 33 is 1178 kJ/kg. This calorie is as smallas about 50% of the calorie (2137 kJ/kg) required for raising thetemperature of the heat medium from 269° C. to 450° C., and thetemperature of the exhaust gas is lowered just to about 140° C. at theexhaust gas outlet of the boiler 30. In this case, therefore, heatenergy corresponding to the difference between the temperature (140° C.)of the exhaust gas at the outlet of the boiler 30 and the atmospherictemperature is released to the atmosphere without being utilized, thusresulting in energy loss.

In this embodiment, to eliminate such energy loss and to effectivelyutilize the calorie of the exhaust gas C which is released to theatmosphere without being utilized, 45% of the heat medium (at, e.g.,about 100° C.) obtained as the high temperature water in the lowpressure economizer 31 is branched and supplied to the heat exchanger 54in the heat pump 50. As a result, the heat medium to be heated by theheat pump 50 can be preheated by utilizing the calorie of the exhaustgas C released to the atmosphere without being utilized, and the energyefficiency of the heat pump 50 can be further increased. Also, thetemperature of the exhaust gas C released to the atmosphere can belowered and hence heat energy loss can be reduced. For example, when theheat medium supplied to the boiler 30 at 30° C. is heated to about 100°C. by the low pressure economizer 31, the temperature of the exhaust gasC released to the atmosphere is lowered from 140° C. to a level nearerto the atmospheric temperature (e.g., about 60° C. or below), and thefuel energy applied to the combustor 12 is substantially all recovered.

Energy consumption efficiency, i.e., coefficient of performance (COP),indicating the performance of the heat pump 50 is defined as a ratio ofthe motive power applied to the heat pump 50 by the compressor 53 to thecalorie applied to the steam produced by the heat exchanger 54. Calorieused for heating the heat medium in the heat exchanger 54 is expressedby a total of the calorie recovered into the heat medium from theexterior by the evaporator 57 and the motive power used by thecompressor 53 for pressurizing the heating medium. When overall systemefficiency is calculated by setting the fuel energy applied to thecombustor 12 as a denominator and a total of the amount of electricpower generated by the generator 14 and the calorie supplied to the heatutilization facility 1 as a numerator with the COP value being aparameter, the overall system efficiency exceeds 100% if the COP valueexceeds 1.7, and becomes 128% if the COP value is increased to 5. Thisis resulted from the effect obtained by taking in the heat energy by theevaporator 57 from the exterior in addition to the fuel energy appliedto the combustor 12. Further, the motive power used by the circulationpump 35 and the high pressure pump 39 in the boiler 30 also contributesto heating the heat medium.

Thus, while the overall efficiency of a general cogeneration system isabout 80%, the overall efficiency of the heat energy supply system ofthis embodiment is notably higher than 80%. By calculation, the heatenergy supply system of this embodiment is able to cut the amount ofCO₂, which is generated from the system and adversely affects the globalwarming, about 37% as compared with the general cogeneration systemhaving the overall efficiency of 80%. The heat loss in the heat energysupply system of this embodiment is expressed by calorie correspondingto the temperature difference between the exhaust gas C released to theatmosphere from the boiler 30 and the atmosphere A sucked into thecompressor 11. Accordingly, the overall efficiency of the heat energysupply system of this embodiment exceeds 100% by taking in largercalorie by the evaporator 57 from the exterior than that heat loss.

Further, in this embodiment, the motive power obtained by the steamturbine 51 is all used as forces for driving the compressor 53 and thetwo-phase flow expansion turbine 52 in the heat pump 50 withoutconverting the motive power obtained by the steam turbine 51 to electricpower. There is hence no loss attributable to conversion to electricpower in the heat pump 50. In addition, since the steam discharged fromthe steam turbine 51 and the steam produced by the heat pump 50 aremixed and transported to the heat utilization facility 1 through thecommon steam pipe 74, a larger amount of heat medium can be supplied tothe heat utilization facility 1 without causing loss. Those points arealso major advantages with the heat energy supply system of thisembodiment.

Another major advantage is that, when there is existing equipmentreleasing unused waste heat to the atmosphere, such as an engine and aboiler, the heat energy supply system of this embodiment can beconstructed with ease by employing such existing equipment.

(2) Second Embodiment

FIG. 2 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a second embodiment of the presentinvention. Note that, in FIG. 2, similar components to those in FIG. 1are denoted by the same reference numerals, and a duplicate descriptionof those components is omitted here.

As shown in FIG. 2, this second embodiment differs from the firstembodiment in the arrangement of a heat pump 50A, namely in that theheat medium from the boiler 30 is supplied to a heat medium cycle forthe heat pump 50A without using the above-mentioned different heatingmedium, such as TFE, and steam obtained in the heat medium cycle issupplied to the heat utilization facility 1. As a result, a heatexchanger for making heat exchange between the heat medium supplied tothe heat utilization facility 1 and the heating medium for heating theformer (i.e., the heat exchanger 54 in FIG. 1) is omitted.

The heat pump 50A comprises the steam turbine 51 driven by the heatmedium (steam) supplied from the boiler 30 through the pipe 42, atwo-phase flow expansion turbine 52A and compressors 53A, 53B which arecoaxially coupled to the steam turbine 51, and a heat exchanger(evaporator) 54A for heating the heat medium (high temperature water),which is supplied from the boiler 30 through the pipe 38, by utilizingexternal heat (such as waste heat from the heat utilization facility 1or heat obtained from environment).

In this embodiment, the pipe 38 extending from the low pressureeconomizer 31 is connected to the two-phase flow expansion turbine 52A.The two-phase flow expansion turbine 52A is connected to the compressor53A in the upstream stage through the heat exchanger 54A, and thecompressor 53A is connected to the compressor 53B in the downstreamstage through a pipe 60, a mixer 61, and a pipe 62. Further, a branchpoint 80 is provided in the pipe 38 connecting the low pressureeconomizer 31 and the two-phase flow expansion turbine 52A to eachother, and a pipe 81 branched from the pipe 38 at the branch point 80 isconnected to the mixer 61. A control valve 82 is disposed in the pipe81, and a flow rate ratio at which the heat medium is distributed to thepipes 38, 81 is adjusted depending on the opening degree of the controlvalve 82.

The heat exchanger 54A includes a pipe 83 disposed therein for passageof, e.g., the wastewater of the heat utilization facility 1 or theatmosphere. A partition 84 is disposed inside the heat exchanger 54Asuch that an upper space in the heat exchanger 54A is divided into twoparts on the side closer to the two-phase flow expansion turbine 52A andon the side closer to the compressor 53A.

The remaining arrangement is the same as that of the above-describedfirst embodiment, and this second embodiment can also provide the sameadvantages as those obtained with the first embodiment. Further, theheat energy supply system of this second embodiment can be constructedby utilizing the existing engine and boiler in a similar way. Inaddition, this second embodiment can provide the operating advantages asfollows.

Since the heat medium supplied from the boiler 30 is used as the mediumin the heat pump 50A in this embodiment, the two-phase flow expansionturbine 52A can produce a larger motive force, for example, by designingthe system in which the heat medium heated to a state substantiallyunder the saturation conditions flows into the two-phase flow expansionturbine 52A.

For example, when the heat medium is prepared at the outlet of the lowpressure economizer 31 in the boiler 30 as high temperature water atabout 130° C. and 0.5 MPa, i.e., a state near the saturation conditions,the opening degree of the control valve 82 is adjusted such that theheat medium is supplied to the two-phase flow expansion turbine 52Athrough the branch point 80 at a proportion of 80% and the supplied heatmedium is depressurized to about 0.01 MPa at 46° C. by the two-phaseflow expansion turbine 52A. The heat medium supplied to the heatexchanger 54A is evaporated at a predetermined proportion (e.g., about14%) during the expansion process in the two-phase flow expansionturbine 52A so as to form a two-phase flow, and the liquid phaseseparated from the steam phase is accumulated in a lower portion of theheat exchanger 54A. In this case, the liquid phase is heated andevaporated by utilizing factory waste heat or town waste heat at about50-60° C. When the outlet pressure of the two-phase flow expansionturbine 52A is further reduced (for example, to about 0.002 MPa), thetemperature in the heat exchanger 54A is correspondingly further lowered(for example, to about 18° C.). In such a case, the heat medium can beevaporated by utilizing heat of the infinitely existing atmosphere.

The steam present in the upper space of the heat exchanger 54A at apredetermined pressure (e.g., about 0.01 MPa) is pressurized (forexample, to about 0.4 MPa) by the compressors 53A, 53B and is suppliedas a heat source to the heat utilization facility 1. In the mixer 61disposed between the compressor 53A in the upstream stage and thecompressor 53B in the downstream stage, the heat medium in the state ofhigh temperature water is sprayed through the pipe 81 branched from thebranch point 80 to lower the temperature of the heat medium suppliedfrom the compressor 53A to the compressor 53B.

The reason is that when compressing steam of 0.01 MPa to 0.4 MPa, forexample, unless the steam is cooled midway, the steam temperaturereaches about 490° C. even if the compression efficiency is 100%, andreaches about 550° C. if the compression efficiency is 85%. In thelatter case, energy corresponding to the temperature difference betweenthe saturation temperature, i.e., 46° C., of the heat medium (water) at0.01 MPa and 550° C. is required as motive power for driving thecompressors 53A, 53B. In compression of gas, the lower gas density, thelarger is motive power required for the compression. In view of theabove, the flow rate of the heat medium is adjusted by the control valve82 so that the high temperature water of 0.5 MPa is branched from thebranch point 80 and poured into the mixer 61 for spray to the steamduring the compression process, thereby lowering the steam temperature.

In this embodiment, the two compressors 53A, 53B are installed and themixer 61 is disposed between them. For the purpose of reducing themotive power required for driving the compressors, however, it is alsoconceivable to install three or more compressors and to dispose a mixerbetween every two adjacent compressors.

With this embodiment, as described above, by spraying the steam to theheat medium in the state of super heat steam flowing out of thecompressor 53A, the temperature of the super heat steam can be easilylowered to the saturation temperature. Alternatively, in the step ofspraying the heat medium, the heat steam may be sprayed until the steamis slightly humidified. In this case, the heat medium is in the state ofhumid steam at the inlet of the compressor 53B in the downstream stage,but water droplets are evaporated inside the compressor 53B. Thus, atemperature rise in the compressor 53B can be suppressed and the motivepower required for driving the compressors can be reduced as a whole.From the viewpoint of obtaining higher efficiency, an amount of the heatmedium sprayed in the mixer 61 is preferably adjusted such that thesteam temperature at the outlet of the compressor 53B is held at thetemperature (e.g., about 140° C.) utilized by the heat utilizationfacility 1.

The motive power used by the compressors 53A, 53B is supplied from thesteam turbine 51 and the two-phase flow expansion turbine 52A. Since theheat medium supplied to the heat utilization facility 1 is used as themedium in the heat pump 50A, it is possible to cool the heat medium bydirectly spraying the branched heat medium at the midpoint between thecompressors 53A, 53B, and to omit a large-sized heat exchanger (i.e.,the heat exchanger 54 in the embodiment of FIG. 1) which is requiredwhen the heat medium is indirectly cooled by using the dedicated heatingmedium, such as TFE. Because the weight of the two evaporators 54, 57occupies half or more of the total weight of the heat pump 50 shown inFIG. 1, the omission of one of those two evaporators like thisembodiment greatly contributes to simplifying the equipment arrangement.Further, when the heat medium is heated through the heat exchange withanother heating medium, such as TFE, the temperature difference isrequired between the heat medium to be heated and the heating medium forheating the former. However, that temperature difference is no longerrequired and higher efficiency can be obtained correspondingly.

Moreover, in this embodiment, the pressure in the heat exchanger 54A islow (e.g., about 0.01 MPa) and the fluid density at each of the outletof the two-phase flow expansion turbine 52A and the inlet of thecompressor 53A is relatively small. Accordingly, by connecting theoutlet of the two-phase flow expansion turbine 52A and the inlet of thecompressor 53A to the upper space in the heat exchanger 54A as shownFIG. 2, the need of arranging a pipe to increase the fluid speed midwaycan be eliminated. In addition, since the interior of the heat exchanger54A is divided by the partition 84 into two parts, water droplets at theoutlet of the two-phase flow expansion turbine 52A can be prevented fromdirectly flowing into the compressor 53A. The liquid phase remains at astandstill inside the heat exchanger 54A. If the heat exchangeefficiency between the liquid phase and the pipe 83 is poor, it is morepreferable to install a stirrer (not shown) for causing the liquid phaseto flow in a forcible manner and to provide an internal partition (notshown) so that a uniform flow is formed and heat conduction is promoted.

(3) Third Embodiment

FIG. 3 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a third embodiment of the presentinvention. Note that, in FIG. 3, similar components to those in theabove-referenced drawings are denoted by the same reference numerals,and a duplicate description of those components is omitted here.

As shown in FIG. 3, this third embodiment differs from the foregoingembodiments in that a ratio of generated power output to thermal outputis made variable, i.e., that respective drive shafts of the steamturbine 51 and the compressor 53B are coupled to each other through avariable speed reducer 85.

Also, a condenser 86 for condensing the steam discharged from the steamturbine 51 after performing expansion work therein is connected to theoutlet of the steam turbine 51 through a pipe 87. The condenser 86 isconnected through a pipe 90 to a joining unit 89 disposed in a pipe 88interconnecting the heat utilization facility 1 and the circulation pump35. Control valves 91, 92 are disposed respectively in the pipes 88, 90.Further, a control valve 93 is disposed in a pipe 71 interconnecting theextraction port of the steam turbine 51 and the joining unit 73.

The remaining arrangement is the same as that of the above-describedsecond embodiment, and this third embodiment can also provide the sameadvantages as those obtained with the second embodiment. Further, theheat energy supply system of this third embodiment can be constructed byutilizing the existing engine and boiler in a similar way. In addition,this third embodiment can provide the operating advantages as follows.

The compressors 53A, 53B are coaxially coupled to not only the two-phaseflow expansion turbine 52A and the steam turbine 51, but also to the gasturbine 10. Therefore, the rotatory power produced from the turbine 13can be utilized as the motive power for driving the compressors 53A,53B. The motive power remained after driving the compressors 53A, 53B isconverted to electrical energy by the generator 14.

A ratio of heat to electric power required in the heat utilizationfacility 1, etc. varies. Corresponding to such a variation, the systemof this embodiment is able to continuously change a proportion of heatsupply with respect to the total amount of supplied energy from 0%(supply of electric power: 100%) to 100% (supply of electric power: 0%).

When only electric power is supplied, the control valve 40 is closed tomake 0 (zero) the flow rate of steam produced by the heat pump 50A (heatexchanger 54A). In this state, the rotation speed of the circulationpump 35 is controlled to be matched with the conditions of super heatsteam that is finally produced by the high pressure super-heater 34 inthe boiler 30, thereby adjusting the amount of the heat medium suppliedto the boiler 30. When the control valve 40 is closed and no heat mediumis introduced to the pipe 38 like this case, the temperature of theexhaust gas C discharged from the boiler 30 rises.

Here, the amount of the heat medium supplied by the circulation pump 35can be decided by dividing the calorie given to the heat medium in theboiler 30 by the calorie required per unit flow rate. The calorie givento the heat medium in the boiler 30 can be calculated from both thetemperature difference of the exhaust gas between the outlet of theturbine 13 and the outlet of the boiler 30 and the flow rate of theexhaust gas discharged from the turbine 13. The calorie required perunit flow rate can be obtained from the difference between the enthalpyof the heat medium at the outlet of the circulation pump 35 and theenthalpy of the heat medium at the outlet of the high pressuresuper-heater 34.

By closing the control valve 93 to cut off the supply of the heat mediumextracted from the steam turbine 51 to the heat utilization facility 1and opening the control valve 92, the heat medium used for driving thesteam turbine 51 is all supplied to the condenser 86 and condensed forreturn to water. Because no heat medium flows into the two-phase flowexpansion turbine 52A and the compressors 53A, 53B, the energy loss canbe reduced by disconnecting the variable speed reducer 85 such that itis released from the state coupled to the steam turbine 51.

On the other hand, when electric power and heat are supplied to the heatutilization facility 1 at the same time, proportions of the flow rate ofthe heat medium supplied to the heat pump 50 and the high pressureeconomizer 32 through the branch point 36 are adjusted by controllingthe opening degree of the control valve 40 and the rotation speed of thecirculation pump 35. The flow rate of the heat medium sprayed to theheat medium in the state of super heat steam at the midpoint between thecompressors 53A, 53B is adjusted by controlling the opening degree ofthe control valve 82 so that the heat medium is sprayed at a constantratio with respect to the flow rate of the heat medium flowing into thecompressor 53B.

Because the performance of the heat pump 50A is decided depending on thepressure in the evaporator 54A, the rotation speeds of the compressors53A, 53B are controlled by the variable speed reducer 85 so as to holdthe pressure in the evaporator 54A at a predetermined value. During aperiod in which a heat demand is small, the control valve 93 is closedto maximize the output of the steam turbine 51. If there is a demandrequiring a further increase of the thermal output after the flow rateof the heat medium flowing through the two-phase flow expansion turbine52A has increased to a level at which the evaporator 54A cansufficiently develop its capability of evaporating the heat medium, theopening degree of the control valve 93 is enlarged to increase the flowrate of the heat medium introduced to the joining unit 73. By enlargingthe opening degree of the control valve 93, the flow rate of the heatmedium introduced to the joining unit 73 is increased correspondingly,while the output of the steam turbine 51 is reduced and so is the amountof electric power generated by the generator 14 in a reverseproportional relation. At the time when the amount of generated electricpower becomes 0 (zero), the thermal output in the entire system ismaximized.

When the steam discharged from the steam turbine 51 is introduced to thecondenser 86 and condensed therein, the resulting condensation heat isrecovered by cooling water and released to the exterior. Accordingly,the heat loss of the system is given by the calorie of the exhaust gas Cdischarged through the stack 43 and such condensation heat. In the statewhere the control valve 92 is closed and no heat medium flows into thecondenser 86 under the conditions of maximizing heat energy, the overallenergy efficiency of the system shows a maximum value.

In the case of supplying energy only as thermal output, a percentage ofenergy of the heat medium capable of being supplied to the heatutilization facility 1 with respect to fuel energy supplied to thecombustor 12 is in the range of 180-220% depending on the temperature ofwaste heat available by the evaporator 54A and the efficiencies of thecompressors 53A, 53B. Steam energy available in a general boiler isabout 90% of input fuel energy and never exceeds 100%. In the system ofthis embodiment, since the motive power produced by the gas turbine 10is also used as a driving force for the heat pump 50A, the total energyamount capable of being supplied to the heat utilization facility 1 isable to exceed 200% depending on the conditions by employing not onlythe fuel energy supplied to the combustor 12, but also energy of theatmosphere or waste heat utilized by the evaporator 54A.

(4) Fourth Embodiment

FIG. 4 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a fourth embodiment of the presentinvention. Note that, in FIG. 4, similar components to those in theabove-referenced drawings are denoted by the same reference numerals,and a duplicate description of those components is omitted here.

As shown in FIG. 4, this fourth embodiment differs from the foregoingembodiments in that the steam discharged from the steam turbine 51 afterperforming expansion work therein and the steam heated by the heatexchanger 54A are supplied to corresponding different heat utilizationfacilities 1A, 1B, respectively.

In this fourth embodiment, the steam supply line 70 includes a pipe 75interconnecting the steam turbine 51 and a heat utilization facility 1A,e.g., a factory, and a pipe 76 interconnecting the compressor 53B andanother heat utilization facility 1B, e.g., a heated swimming pool. Theheat medium used for driving the steam turbine 51 and the heat mediumheated by the heat exchanger 54A are supplied respectively to the heatutilization facilities 1A, 1B through the pipes 75, 76. The heat mediumshaving been utilized as heat sources in the heat utilization facilities1A, 1B and condensed are discharged from the heat utilization facilities1A, 1B and then joined with each other by a joining unit 94 for returnto the circulation pump 35.

The remaining arrangement is the same as that of the above-describedsecond embodiment, and this fourth embodiment can not only provide thesame advantages as those obtained with the second embodiment, but alsosupply the heat mediums to a plurality of heat utilization facilities asrequired. Further, the heat energy supply system of this fourthembodiment can be constructed in a similar way. While this fourthembodiment has been described in connection with the case of supplyingenergy to a plurality of heat utilization facilities in the systemaccording to the second embodiment, the arrangement of this fourthembodiment is also applicable to the case of supplying energy to aplurality of heat utilization facilities in the systems according to theother above-described embodiments.

(5) Fifth Embodiment

FIG. 5 is a system flowchart showing the overall arrangement of a heatenergy supply system according to a fifth embodiment of the presentinvention. Note that, in FIG. 5, similar components to those in theabove-referenced drawings are denoted by the same reference numerals,and a duplicate description of those components is omitted here.

As shown in FIG. 5, this fifth embodiment differs from the foregoingembodiments in that, instead of waste heat of an engine (such as the gasturbine 10), a boiler 30A installed in any of various facilities, e.g.,a sanitation factory, is employed as a heat source for generating thesteam (heat medium) to drive a heat pump 50A. While one example of theboiler 30A is an incinerator boiler in the sanitation factory, theboiler 30A is not limited to such an example and may be any other boilerso long as it is able to heat a heat medium for conversion to steam,e.g., a boiler using heavy oil or tires as fuel. In this embodiment,water pumped up from a river 96 by a pump 95 is introduced to the heatexchanger 54A as a heating medium used in the heat pump 50A to heat theheat medium. In the thus-arranged system of this embodiment, heat energyis supplied to the heat utilization facility 1, such as a heatedswimming pool, with high efficiency by adding calorie obtained from theriver water to calorie obtained from a heat exchanger 30Aa which isdisposed in the boiler 30A.

The heat medium returned from the heat utilization facility 1 ispressurized to a setting pressure (e.g., about 7 MPa) by the circulationpump 35 and then supplied to the boiler 30A for heating in the heatexchanger 30Aa. The heat medium coming into the state ofhigh-temperature, high-pressure water is supplied to an expansionturbine 52A through a pipe 38, and the heat medium coming into the stateof high-pressure super heat steam is supplied through a pipe 42 to thesteam turbine 51 for driving the heat pump 50A. In the case of the heatmedium being water, when the water is expanded to about 0.002 MPa by theexpansion turbine 52A, it can be evaporated by heat infinitely obtainedfrom the river 96 because the saturation temperature lowers to 17.5° C.The water of the river 96 is supplied to the heat exchanger 54A througha pipe 83 by the pump 95. If the river water is highly contaminated, afilter is disposed in the pipe 83 to remove insoluble materials.

The evaporated saturated steam is compressed to a setting pressure(e.g., about 0.4 MPa) by the compressors 53A, 53B. In order to reducecompression motive forces to be applied from the compressors 53A, 53B,the heat medium in the state of high temperature water is sprayed tocool the steam at the midpoint between the compressors 53A, 53B. Themotive power for driving the compressors 53A, 53B is provided by energyproduced when the heat medium in the state of super heat steam at thesetting pressure (e.g., about 7 MPa) is depressurized by the steamturbine 51 to a pressure (e.g., about 0.4 MPa) suitable for use in theheat utilization facility 1. The steam exiting the steam turbine 51 andthe steam exiting the compressor 53B are mixed with each other in thejoining unit 73 and supplied as a heat source to the heat utilizationfacility 1.

This fifth embodiment can also provide the same advantages as thoseobtained with the foregoing embodiments, and the heat energy supplysystem of this fifth embodiment can be constructed in a similar way byusing the existing boiler. By utilizing the heat of the river 96 aswell, the calorie capable of being supplied from the same boiler 30A canbe increased about 1.8 times depending on the conditions as comparedwith the system in which only the steam generated by the existing boiler30A is supplied to the heat utilization facility 1.

While the foregoing embodiments have been described in connection withthe case of using water as the heat medium supplied to the heatutilization facility, other suitable medium, such as carbon dioxide,ammonia or trifluoroethanol (TFE), may also be used as the heat mediumbecause the heat medium is circulated in a closed system and will notflow out to the exterior. As a matter of course, although those othermediums may be each used alone, they may also be used in mixed form ofseveral kinds of mediums or mixed with water. Further, when a harmlessand mixable medium is used as the heat medium, the closed system is notessential. In such a case, the heat medium for driving the steam turbine51 and the heat medium heated by the heat pump 50 or 50A may be suppliedfrom different supply sources. In the case of using plural kinds of heatmediums, when the heat medium for driving the steam turbine 51 and theheat medium heated by the heat pump 50 or 50A are supplied to differentheat utilization facilities and circulated in respective closed systems,both the heat mediums are not necessarily required to be mixable.

(6) Sixth Embodiment

In the system of FIG. 1, the heat medium having been utilized in theheat utilization facility 1 is condensed and returned to the circulationpump 35. On the other hand, this sixth embodiment is featured inomitting the pipe through which the heat medium having been utilized asa heat source in the heat utilization facility 1 and condensed issupplied to the boiler 30 in a circulating manner, and in supplying theheat medium to the circulation pump 35 from other supply source than theheat utilization facility 1.

It is supposed that, instead of utilizing only the steam (heat medium)supplied from the steam supply line 70, the heat utilization facility 1employs the steam in a reaction process. The steam having been used inthe reaction process has a difficulty in directly circulating it to theheat pump for reuse. In this embodiment, therefore, the pipe throughwhich the heat medium having been utilized as a heat source in the heatutilization facility 1 and condensed is supplied to the boiler 30 in acirculating manner is not disposed, and water from other supply source,e.g., a river or the underground, than the heat utilization facility 1is cleaned and supplied to the circulation pump 35. With such a systemarrangement, because of no need of installing the return pipe from theheat utilization facility 1 to the circulation pump 35, an effect ofcutting the installation cost is increased as the distance between theheat pump 50 and the heat utilization facility 1 increases.

(7) Seventh Embodiment

In the second embodiment shown in FIG. 2, the heat medium supplied tothe heat utilization facility 1 is also employed as the heat medium foruse in the heat pump 50. This seventh embodiment uses water as thecommon heat medium.

The following description is made in comparison with a systemarrangement in which the heat pump has the same arrangement as that of aknown heat pump and the heat medium is just replaced with water. FIG. 6is a system flowchart showing the overall arrangement of a heat energysupply system utilizing water as the heat medium, the system includingthe known heat pump. Comparing with FIG. 2 described above, the heatpump 50A includes one compressor 53, and does not include the mixer 61connected to the pipe branched from the pipe 38 interconnecting the lowpressure economizer 31 and the two-phase flow expansion turbine 52A. Inthe system of FIG. 6, when gas is compressed by the compressor 53 of theheat pump 50A, a larger temperature rise is caused as the gas has lowerdensity. For example, the density of steam at 0.01 MPa and 46° C. is0.068 kg/m³ that is just 13% of 0.52 kg/m³, i.e., the density of R-11 asone of coolants. In the case of using R-11, therefore, even when it iscompressed to 0.4 MPa, the temperature rises up to just 185° C. On theother hand, when the steam is compressed to the same level, thetemperature rises up to 490° C. Because the saturation temperature ofwater at 0.4 MPa is 144° C., the motive power required for raising thetemperature from 144° C. to 490° C. is merely converted to heat, thusresulting in a significant reduction of the system efficiency. Thus, thesystem having the same arrangement as that of the known heat pump andsimply employing water as the heat medium accompanies a large efficiencyreduction and hence has a difficulty in putting it into practical use.

To avoid that problem, in this embodiment using water as the heat mediumin the heat pump, the system has to be modified as shown in FIG. 2. Morespecifically, the compressor 53 of the heat pump 50A is divided intoplural stages, and the steam is cooled to increase density at theintermediate between the divided compressor stages, thereby reducing thecompression motive power required.

A manner of cooling the steam at the intermediate between the dividedtwo compressor stages can be realized by not only spraying water to thesteam as described above, but also installing a heat exchanger. In thelatter case, although the heat exchanger is installed outside containersfor the compressors 53A, 53B and hence the equipment size is enlarged,the steam temperature can be adjusted with higher accuracy.

In addition to simple condensation of the steam to be utilized as heat,the heat utilization facility 1 can also utilize the steam in other waysas follows. First, an absorption freezer using lithium bromide as acoolant is installed in the heat utilization facility, and hightemperature steam is utilized to evaporate the coolant, thereby coolingthe heat utilization facility. Secondly, the steam is directly injectedor sprayed to products in a chemical process or a drying process. Inthis case, the heat utilization facility 1 is not required to includethe condenser for condensing the steam.

1. A heat energy supply method for supplying a heat medium to a heatutilization facility, the method comprising the steps of: driving a heatpump which includes a steam turbine, by steam obtained by heating a heatmedium in a boiler; heating the heat medium in a heat exchanger byemploying waste heat or heat obtained from environment, therebyproducing the steam at a setting temperature; compressing the steam by acompressor coaxially coupled with the steam turbine; supplying the steamdischarged from the steam turbine and the steam heated by the heatexchanger to the heat utilization facility; and providing the motivepower for driving the heat pump by energy produced when the heat mediumin a state of super heated steam at the setting pressure from theboiler, is depressurized by the steam turbine to a pressure suitable foruse in the heat utilization facility.
 2. The heat energy supply methodaccording to claim 1 further comprising the step of expanding the heatmedium supplied from the boiler by an expansion turbine and supplyingthe expanded heat medium to the heat exchanger.
 3. The heat energysupply method according to claim 2 further comprising the step ofsupplying the heat medium to a steam flowing line between twocompressors.
 4. The heat energy supply method according to claim 1,further comprising the step of joining and mixing the steam dischargedfrom the steam turbine and the steam produced by the heat exchanger witheach other.
 5. The heat energy supply method according to claim 1further comprising the step of circulating, to the boiler, the heatmedium condensed after being utilized as steam in the heat utilizationfacility.
 6. The heat energy supply method according to claim 1, furthercomprising the step of heating the heat medium by introducing the wasteheat or the heat obtained from environment directly into the heatexchanger.
 7. The heat energy supply method according to claim 3,further comprising the step of using as a heating source in the boiler,exhaust gas from an engine for converting combustion energy to a drivingforce and coupling a steam turbine and one of the compressors or theextension turbine which is driven by motor power obtained from the steamturbine, by a variable speed reducer in the heat pump.
 8. The heatenergy supply method according to claim 1, further comprising the stepof using water as the heat medium.